Project Summary: This proposal is intended to provide Dr. Marquez de la Plata the education and experience required to become a successful independent investigator. Dr. Marquez de la Plata is a well-trained neurpsychologist who is completing a productive post-doctoral fellowship, and has identified several immediate objectives necessary to his ultimate goal of an independent career centered on patient oriented research by integrating neuroradiologic and neurocognitive assessment techniques. The career development award provides an opportunity for him to meet his short-term goals of obtaining advanced training in neuroimaging techniques, research design and statistical analysis, and functional neuroanatomy. {The goal of this research proposal is to determine the utility of neuroimaging modalities, including conventional MRI and Diffusion Tensor Imaging (DTI), as a biomarker of outcome after diffuse axonal injury (DAI). Preliminary data from our group indicates that DTI has a greater correlation to outcome than conventional structural MRI.} This proposal is designed to identify DTI parameters that can be utilized reliably in clinical trials of DAI-directed therapies. We will accomplish our objectives by obtaining acute MRI scans on consecutive patients with DAI, obtaining rescans six-months post-injury, and collecting functional and neurocognitive outcome data on these patients. The North Texas Traumatic Brain Injury Research Center within the University of Texas Southwestern Medical Center is an ideal environment to succesfully achieve the aims of both the career development and research project aspects of this proposal, as the university offers the didactic and mentoring experiences essential for Dr. Marquez de la Plata's training, and the research center offers the infrastructure support to accomplish the goals of the research plan. Relevance: A reliable and valid means of assessing white matter injury severity in patients with DAI lesions is important for guiding clinical management, assessing prognosis, and counseling families, as well as for stratifying injury severity when selecting patients for clinical trials. Additionally, quantitative assessments of DAI may be useful as surrogate endpoints for clinical trails directed at white matter injury.